// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package os
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import (
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"errors"
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"internal/poll"
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)
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// Portable analogs of some common system call errors.
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var (
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ErrInvalid = errors.New("invalid argument") // methods on File will return this error when the receiver is nil
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ErrPermission = errors.New("permission denied")
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ErrExist = errors.New("file already exists")
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ErrNotExist = errors.New("file does not exist")
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ErrClosed = errors.New("file already closed")
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ErrNoDeadline = poll.ErrNoDeadline
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)
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type timeout interface {
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Timeout() bool
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}
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// PathError records an error and the operation and file path that caused it.
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type PathError struct {
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Op string
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Path string
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Err error
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}
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func (e *PathError) Error() string { return e.Op + " " + e.Path + ": " + e.Err.Error() }
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// Timeout reports whether this error represents a timeout.
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func (e *PathError) Timeout() bool {
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t, ok := e.Err.(timeout)
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return ok && t.Timeout()
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}
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// SyscallError records an error from a specific system call.
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type SyscallError struct {
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Syscall string
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Err error
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}
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func (e *SyscallError) Error() string { return e.Syscall + ": " + e.Err.Error() }
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// Timeout reports whether this error represents a timeout.
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func (e *SyscallError) Timeout() bool {
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t, ok := e.Err.(timeout)
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return ok && t.Timeout()
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}
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// NewSyscallError returns, as an error, a new SyscallError
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// with the given system call name and error details.
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// As a convenience, if err is nil, NewSyscallError returns nil.
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func NewSyscallError(syscall string, err error) error {
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if err == nil {
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return nil
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}
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return &SyscallError{syscall, err}
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}
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// IsExist returns a boolean indicating whether the error is known to report
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// that a file or directory already exists. It is satisfied by ErrExist as
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// well as some syscall errors.
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func IsExist(err error) bool {
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return isExist(err)
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}
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// IsNotExist returns a boolean indicating whether the error is known to
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// report that a file or directory does not exist. It is satisfied by
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// ErrNotExist as well as some syscall errors.
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func IsNotExist(err error) bool {
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return isNotExist(err)
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}
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// IsPermission returns a boolean indicating whether the error is known to
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// report that permission is denied. It is satisfied by ErrPermission as well
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// as some syscall errors.
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func IsPermission(err error) bool {
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return isPermission(err)
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}
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// IsTimeout returns a boolean indicating whether the error is known
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// to report that a timeout occurred.
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func IsTimeout(err error) bool {
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terr, ok := underlyingError(err).(timeout)
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return ok && terr.Timeout()
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}
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// underlyingError returns the underlying error for known os error types.
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func underlyingError(err error) error {
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switch err := err.(type) {
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case *PathError:
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return err.Err
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case *LinkError:
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return err.Err
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case *SyscallError:
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return err.Err
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}
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return err
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}
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